You could try peanut butter, it is natural and since it is on the dogs face, you don't want to use anything toxic. Put the peanut butter on the hair and give it a few minutes to penetrate the pine sap. Then simply wipe it off and the pine pitch should come off with the peanut butter.

I used that method on my horses when they got pitch on their coats, I don't think dogs would be any different?

What kind of dog is he? I can't recognize it from the pictures. But then again, some puppies look so different from the full grown version.